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Finding the Fourth Proportional to 789.76, 1,089.68 and 490.87

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Solution

The fourth proportional to 789.76, 1,089.68 and 490.87 is: 677.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    789.76 : 1,089.68 = 490.87 : x
  2. Step 2: Convert to fraction form
    789.76/1,089.68 = 490.87/x
  3. Step 3: Cross multiply
    789.76x = 1,089.68 × 490.87
  4. Step 4: Simplify right side
    789.76x = 534,891.22
  5. Step 5: Solve for x
    x = 534,891.22/789.76
  6. Step 6: Final answer
    x = 677.28

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Double scale
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.